This invention relates generally to furnaces and more particularly to hot air furnaces that are adapted to burn wood.
One of the major problems with conventional wood burning furnaces has been the tendency for an extremely hot fire to develop. This is attributed primarily to the manner in which combustion air is supplied to the firebox. Typically air is introduced beneath the grates on which the wood is supported and thus flows upwardly through the center of the fire to cause a hotter fire than is necessary or desirable. Consequently, excessive wood is consumed and the extreme heat causes the grates to become warped.
Incomplete combustion has been another problem associated with conventional wood burning furnaces. The resultant inefficiency of the combustion process increases the amount of fuel required to maintain adequate heating and is further undesirable from an air pollution standpoint. It is also common for smoke and ash to escape from the furnace when the door is open to replenish the wood supply. Additional leakage occurs because of the manner in which conventional furnaces are constructed. The furnace is usually formed from a plurality of separate sections which are field assembled and caulked with furnace cement or the like at the seams. The cement eventually dries out or otherwise develops leaks, and smoke is thus permitted to escape into the heated areas.
A need therefore remains for an improved furnace which is able to effect efficient combustion with a relatively low temperature fire and without significant smoke leakage. It is the primary object of the present invention to meet this need.
More specifically, it is an object of this invention to provide a furnace which supplies controlled amounts of air for combustion above and to the sides of the fire in order to prevent an excessively hot fire from developing.
Another object of this invention is to provide a furnace of the character described which includes a secondary air intake for assisting in complete combustion prior to the passage of the gases out of the flue.
Still another object of the invention is to provide a furnace of the character described that includes a firebox of unitary construction in order to eliminate the possibility of smoke leakage.
A further object of the invention is to provide a furnace of the character described which includes a bypass damper to channel smoke directly into the flue when the main door of the firebox is opened.
An additional object of the invention is to provide a furnace of the character described that requires less maintenance as compared to conventional furnaces.
Yet another object of the invention is to provide a furnace of the character described in which the heat transfer from the firebox to the circulating air is increased in efficiency as compared to conventional furnaces.
A still further object of the invention is to provide a furnace of the character described that has improved controls for maintaining a uniform temperature and conserving fuel.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description of the drawings.